Summary of the invention
For preventing to flow through overcurrent among the LED when the transition, to consider to adopt and in the circuit of tie point lamp control circuit and LED, insert resistive element, the electric current that utilizes resistive element consumption to flow through when transition prevents to flow through among the LED method of overcurrent.But, in this method, because resistive element also can current sinking when stablize, so the power consumption increase.
The present invention proposes in view of described prior art problems, the electric current that its purpose flows through in semiconductor light sources when being to suppress transition, the loss of electric power when suppressing to stablize.For realizing described purpose, the lighting control device of the lamps apparatus for vehicle that technical scheme 1 relates to, it possesses: the electric current supply control unit, it accepts the supply of electric power from power supply, and control is to the electric current supply of semiconductor light sources; Current detecting unit, it detects the electric current of described semiconductor light sources; Resistive element, its consumption is accompanied by the electric current of energising; Switch element, itself and described resistive element are connected in parallel, and when disconnecting action, be formed on the power-on circuit that comprises described resistive element in the supplying electric current path that connects described electric current supply control unit and described semiconductor light sources, when ON Action, be formed on the bypass resistance of walking around described resistive element in the described supplying electric current path; And switch control unit, whether its detection electric current of judging described current detecting unit is the electric current of expression transition state, when obtaining sure judged result, make described switch element disconnect action, when obtaining the judged result of negating, make described switch element carry out ON Action, wherein, described switch control unit, when the detection electric current of described current detecting unit is before the expression electric current begins to flow or follows the transition state of overcurrent, make described switch element disconnect action, when the detection electric current of described current detecting unit is the electric current of expression stable state, make described switch element carry out ON Action.
(effect) is owing to following the connection of power supply, from the electric current supply control unit to the process of semiconductor light sources supplying electric current, whether the electric current that judgement is supplied with to semiconductor light sources is the electric current of expression transition state, when obtaining sure judged result, be that the electric current that flows through in the semiconductor light sources is when representing the electric current of transition state, switch element disconnects action, in the supplying electric current path that connects electric current supply control unit and semiconductor light sources, form the power-on circuit that comprises resistive element, by the resistive element current sinking, so when transition, can be suppressed at and flow through overcurrent in the semiconductor light sources.On the other hand, owing in the supplying electric current path that connects electric current supply control unit and semiconductor light sources, form when comprising the power-on circuit of resistive element, when the electric current of judging semiconductor light sources is not the electric current of expression transition state, change stable state into from transition state, switch element carries out ON Action, in the supplying electric current path that connects electric current supply control unit and semiconductor light sources, form the bypass resistance of walking around resistive element, resistive element is current sinking not, can be from the electric current supply control unit to the semiconductor light sources supplying electric current, the loss of the electric power in the time of can suppressing to stablize.
In addition, before beginning to flow by electric current or when following the transition state of overcurrent in semiconductor light sources, make switch element disconnect action, in semiconductor light sources, flow through overcurrent in the time that transition can being suppressed, when being the electric current of expression stable state, make switch element carry out ON Action, can not produce current drain by resistive element by electric current in semiconductor light sources, flow through predetermined electric current in the semiconductor light sources, the power consumption in the time of can suppressing to stablize.
The constituted mode of the lighting control device of the lamps apparatus for vehicle that technical scheme 2 relates to is, in the lighting control device of the lamps apparatus for vehicle of in technical scheme 1, putting down in writing, described switch control unit, when the detection electric current of judging described current detecting unit is the electric current of expression stable state, when passing through setting-up time subsequently, make described switch element carry out ON Action.
(effect) is by flowing through the electric current of expression stable state in semiconductor light sources, when passing through setting-up time subsequently, make switch element carry out ON Action, even the electric current that flows through in the semiconductor light sources sharply increases, perhaps the time of transition state has certain width, the chattering phenomenon that perhaps switch on, no power recurs alternately also because the formation of bypass resistance postpones setting-up time, can suppress to flow through in the semiconductor light sources overcurrent reliably.
The constituted mode of the lighting control device of the lamps apparatus for vehicle that technical scheme 3 is related is, in the lighting control device of the lamps apparatus for vehicle of in technical scheme 1 or 2, putting down in writing, described switch control unit, when the detection electric current of judging described current detecting unit is the electric current of expression transition state, disconnect action even respond thirty years of age described switch element of this judgement.
When (effect) is the electric current of expression transition state by the electric current in semiconductor light sources, making immediately, switch element disconnects action, even switch on, the mutual chattering phenomenon that produces continuously of no power, also in the supplying electric current path that connects electric current supply control unit and semiconductor light sources, form the power-on circuit that comprises resistive element immediately, can suppress the generation of overcurrent reliably.
The constituted mode of the lighting control device of the lamps apparatus for vehicle that technical scheme 4 is related is, in technical scheme 1,2, in 3 in the lighting control device of the lamps apparatus for vehicle of any record, the setting means of the constant of described resistive element is, will be when described electric current supply control unit be exported maximum power when non-loaded, the electric current of described semiconductor light sources becomes the resistance value that is less than or equal to maximum rated current and is set at lower limit, will be when described electric current supply control unit to be exported minimum power when non-loaded, the resistance value the when electric current of described semiconductor light sources becomes predetermined electric current is set at higher limit.
(effect) when setting the constant of resistive element, if the resistance value of resistive element is excessive, the electric current that then flows through semiconductor light sources is too small, can't make to flow through predetermined electric current in the semiconductor light sources, and switch element can not carry out ON Action.When switch element does not carry out ON Action, flow through electric current often in the resistive element, can produce power consumption.On the contrary,, then the electric current that flows through in the semiconductor light sources can not be reduced, overcurrent may be caused flowing through in the semiconductor light sources if the resistance value of resistive element is too small.Here, constant as resistive element, being set at will be when the electric current supply control unit be exported maximum power when non-loaded, resistance value when the electric current of semiconductor light sources is less than or equal to maximum rated current is set at lower limit, will be when the electric current supply control unit be exported minimum power when non-loaded, resistance value when the electric current of semiconductor light sources becomes predetermined electric current is set at higher limit, thus, flow through overcurrent in the semiconductor light sources in the time of can being suppressed at transition, can make and when stablizing, flow through predetermined electric current in the semiconductor light sources.
The effect of invention
As can be seen from the above description, the lighting control device according to the related lamps apparatus for vehicle of technical scheme 1 when transition, can suppress to flow through in the semiconductor light sources overcurrent, can be suppressed at the power consumption when stablizing simultaneously.
According to technical scheme 2, can suppress to flow through in the semiconductor light sources overcurrent reliably.
According to technical scheme 3, can suppress the generation of overcurrent reliably.
According to technical scheme 4, when transition, can suppress to flow through overcurrent in the semiconductor light sources, when stablizing, can make and flow through predetermined electric current in the semiconductor light sources.
Embodiment
Below, based on embodiment the specific embodiment of the present invention is described.Fig. 1 is the circuit structure diagram of lighting control device of the lamps apparatus for vehicle of expression the 1st embodiment of the present invention, Fig. 2 is the circuit structure diagram of control circuit, Fig. 3 is the oscillogram that is used to illustrate the action of control circuit, Fig. 4 is the circuit diagram of the annexation of expression contactor and LED, Fig. 5 is the figure that is used to illustrate the constant establishing method of resistive element, and Fig. 6 is the circuit structure diagram of lighting control device of the lamps apparatus for vehicle of expression the 2nd embodiment of the present invention.
In these figure, the lighting control device 10 of lamps apparatus for vehicle, as shown in Figure 1; as a key element of lamps apparatus for vehicle (light-emitting device), have constant current control type switching regulaor 12 and protective circuit 14 and constitute, on the switching regulaor 12; as load, be connected with a plurality of LED16.Each LED16 is connected in series mutually as the semiconductor light sources that is made of semiconductor light-emitting elements, is connected in parallel via the outlet side of protective circuit 14 with switching regulaor 12.
As LED16, can use separately, perhaps also a plurality of LED16 can be one another in series connects as light source module, a plurality of light source modules is connected in parallel uses.In addition, LED16 can be used as head lamp, Sha Chedeng ﹠amp; The light source of various lamps apparatus for vehicle such as taillight, fog lamp and direction indicator lamp.
Switching regulaor 12 possesses transformer T1, capacitor C1, nmos pass transistor 18, control circuit 20, diode D1, capacitor C2, shunt resistance R1, constituting to the mode that each LED16 applies the voltage of the forward voltage (voltage drop) more than or equal to each LED16.At the primary side of the transformer T1 capacitor C1 that is connected in parallel, nmos pass transistor 18 simultaneously is connected in series.Capacitor C1's is one distolateral via mains switch 21, power input terminal 22, is connected with the positive terminal of Vehicular accumulator cell 24, and the other end is connected with the negative pole of Vehicular accumulator cell 24 via power input terminal 26, simultaneously ground connection.The drain electrode of nmos pass transistor 18 is connected with the primary side of transformer T1, source ground, and grid is connected with control circuit 20.At the secondary side of transformer T1, via the diode D1 capacitor C2 that is connected in parallel, the tie point of diode D1 and capacitor C2 is via lead-out terminal 28, is connected with the anode-side of the LED16 of upstream side.The distolateral while ground connection of one distolateral and capacitor C2 of the secondary side of transformer T1, and via shunt resistance R1, be connected with current detecting terminal 30.Current detecting terminal 30 is connected with lead-out terminal 32 via protective circuit 14, and lead-out terminal 32 is connected with the cathode side of the LED16 in downstream.Shunt resistance R1 constitute to detect the current detecting unit of the electric current that flows through among the LED16, the voltage that will produce at the two ends of shunt resistance R1, as the Voltage Feedback corresponding with electric current among the LED16 to control circuit 20.
Nmos pass transistor 18 constitutes the switch element that response is carried out switch motion from the connection of control circuit 20 outputs, cut-off signal (switching signal).When nmos pass transistor 18 carries out ON Action, input voltage from Vehicular accumulator cell (DC power supply) 24 is put aside in transformer T1 with the form of electromagnetic energy, when nmos pass transistor 18 disconnects action, put aside electromagnetic energy in transformer T1 with the form of luminous energy, emit among LED16 via diode D1 from the secondary side of transformer T1.
That is, switching regulaor 12 constitutes, and accepts the supply of electric power from Vehicular accumulator cell 24, and control is to the current control unit of the electric current supply of LED16.Under this situation, the control mode of switching regulaor 12 is, the voltage of current detecting terminal 30 and the voltage of regulation are compared, and according to this comparative result output current controlled.
Specifically, the control circuit 20 that is used for the output current of control switch adjuster 12, for example, as shown in Figure 2, have comparator 34, error amplifier 36, saw-toothed wave generator 38, reference voltage 40, resistor R 2, R3, R4 and capacitor C3 and constitute, the lead-out terminal 42 of comparator 34 directly or amplify the preamplifier (not shown) of usefulness via electric current, be connected with the grid of nmos pass transistor 18, the input terminal 44 that is connected with an end of resistance R 2 is connected with current detecting terminal 30.On input terminal 44, apply voltage by current detecting terminal 30 feedbacks, the voltage that resistor R 2, R3 subtend input terminal 44 apply carries out dividing potential drop, will be put on negative input end of error amplifier 36 by the voltage that dividing potential drop obtains.Error amplifier 36 will be corresponding to the voltage of the difference of voltage that puts on negative input end and reference voltage 40 as threshold value Vth, to the positive input terminal input of comparator 34.Comparator 34 reads in sawtooth waveforms Vs from saw-toothed wave generator 38 to negative input end, and this sawtooth waveforms Vs and threshold value Vth are compared, and switching signal is exported to the grid of nmos pass transistor 18 according to this comparative result.
For example, shown in Fig. 3 (a) and (b), the level of threshold value Vth be in sawtooth waveforms Vs level roughly in the middle of the time, output duty cycle is about 50% switching signal.On the other hand, reduce at the output current that is accompanied by switching regulaor 12, when the level of the voltage of current detecting terminal 30 feedback is lower than reference voltage 40, the level of the threshold value Vth that is obtained by error amplifier 36 raises, shown in Fig. 3 (c), (d), be higher than the switching signal of 50% duty ratio from comparator 34 output duty cycles.Its result, the output current of switching regulaor 12 increases.
On the contrary, increase at the output current of following switching regulaor 12, be higher than reference voltage 40 from the level of the voltage of current detecting terminal 30 feedback, when the level of the threshold value Vth that is obtained by error amplifier 36 reduces, shown in Fig. 3 (e), (f), be lower than the switching signal of 50% duty ratio from comparator 34 output duty cycles.Its result, the output current of switching regulaor 12 reduces.In addition, also can replace saw-toothed wave generator 38, use the triangular-wave generator that produces triangular wave (triangular signal).
On the other hand; protective circuit 14 has resistor R 5 is followed the electric current of energising as consumption resistive element; have nmos pass transistor 46, PNP transistor 48, resistor R 6, R7, capacitor C4 as switch element; have the switch control unit of operational amplifier 50 as the switch motion of control switch unit, this protective circuit 14 is inserted between current detecting terminal 30 and the lead-out terminal 32.
Resistor R 5 is inserted in the supplying electric current path 52 that connects current detecting terminal 30 and lead-out terminal 32, at the two ends of resistance R 5, connects the drain electrode and the source electrode of nmos pass transistor 46 respectively.The positive input terminal of operational amplifier 50 is connected with current detecting terminal 30, negative input end is connected with threshold voltage vt h, the voltage and the threshold voltage vt h that compare current detecting terminal 30, judge whether the electric current that flows through among the LED16 is the electric current of expression transition state, and output is corresponding to the voltage of judged result.Here, so-called transition state is meant that electric current begins to flow through before or flow through the state of overcurrent.
For example, when operational amplifier 50 is lower than threshold voltage vt h at the voltage of current detecting terminal 30, judge the electric current of the electric current of LED16 for the expression transition state, the voltage of output low level is as sure judged result, when the voltage of current detecting terminal 30 surpasses threshold voltage vt h, judge the predetermined electric current of the electric current of LED16 for the expression stable state, the voltage of output high level is as the judged result of negating.If voltage from operational amplifier 50 output high level, then this voltage is via resistor R 7, R6, put on the two ends of capacitor C4, according to the time constant of determining by resistor R 7, R6, capacitor C4, the voltage at capacitor C4 two ends increases, if the voltage at capacitor C4 two ends surpasses the threshold value of nmos pass transistor 46, then nmos pass transistor 46 carries out ON Action.That is, nmos pass transistor 46 begins to carry out ON Action through behind the setting-up time at the voltage from operational amplifier 50 output high level.
When nmos pass transistor 46 is in off-state, in supplying electric current path 52, form the power-on circuit that comprises resistor R 5, if but nmos pass transistor 46 carries out ON Action, then in the supplying electric current path 52 that connects current detecting terminal 30 and lead-out terminal 32, form the bypass resistance of walking around resistor R 5.
That is, when the electric current of LED16 is in an interim state, flow through electric current via the power-on circuit that comprises resistor R 5, this electric current is consumed by resistor R 5.On the other hand, if the electric current of LED16 changes stable state into from transition state, then electric current does not flow through in the resistor R 5, forms the bypass resistance of walking around resistor R 5 by nmos pass transistor 46, flows through predetermined electric current via nmos pass transistor 46.
If when in LED16, flowing through predetermined electric current, the lead that lead-out terminal 28 or lead-out terminal 32 are connected with LED16 as shown in Figure 4, after generation breaks away from from contactor 29,31, the chattering phenomenon that is connected with contactor 29,31 once more, produce do not have among the LED16 that electric current flows through during, then the output of operational amplifier 50 changes low level into by high level, PNP transistor 48 becomes on-state, electric charge moment of putting aside among the capacitor C4 discharges, and nmos pass transistor 46 disconnects action immediately.At this moment, control circuit 20 is followed and is not flow through electric current among the LED16, and the control that is used to make the output current of switching regulaor 12 to increase is so the output voltage of switching regulaor 12 sharply rises.In this process,, then can apply high voltage to LED16 if be connected with LED16 on the switching regulaor 12.But, because nmos pass transistor 46 is in off-state, thus the electric current of LED16 flow through via resistor R 5, even thereby the chattering phenomenon takes place, also can prevent from LED16, to flow through overcurrent.
In addition, the setting means of the constant of resistor R 5 is, will be when the non-loaded maximum power of switching regulaor 12 outputs, the resistance value that the electric current of LED16 is less than or equal to maximum rated current is set at lower limit, during minimum power that will be when switching regulaor 12 output is non-loaded, the resistance value the when electric current of LED16 becomes predetermined electric current is set at higher limit.
That is, if the resistance value of resistor R 5 is excessive, then the electric current that flows through among the LED16 excessively reduces, and can not flow through predetermined electric current among the LED16, and nmos pass transistor 46 can not carry out ON Action simultaneously.If nmos pass transistor 46 does not carry out ON Action, then always flow through electric current via resistor R 5, can produce power consumption.
On the other hand, if the resistance value of resistor R 5 is too small, then the electric current of LED16 can not reduce, and can flow through overcurrent among the LED16.Therefore, in the present embodiment, the resistance value of resistor R 5 is set at such value, that is, when transition, suppresses to flow through overcurrent among the LED16, when stablizing, make and flow through predetermined electric current among the LED16.
Specifically, the setting means of the constant of resistor R 5 (resistance value) is, if produce fluctuation in the temperature characterisitic of consideration resistor R 1 constant resistance element and the temperature characterisitic of reference voltage 40, can produce fluctuation in the output voltage of the switching regulaor 12 when then non-loaded, consider to produce among the forward voltage Vf of LED16 fluctuation simultaneously with temperature characterisitic and individual difference etc., as shown in Figure 5, make under the voltage difference Va of minimum value Vfmin of forward voltage Vf of the maximum Vmax of when the non-loaded output voltage of switching regulaor 12 and LED16, flow through the electric current that is less than or equal to maximum rated current among the LED16, under the voltage difference Vb of the maximum Vfmax of the minimum value Vmin of the output voltage of the switching regulaor 12 when non-loaded and the forward voltage Vf of LED16, flow through electric current among the LED16 more than or equal to rated current.
In said structure, connect and starting switch adjuster 12 at mains switch 21, from switching regulaor 12 to the process of LED16 supplying electric current, when power supply rigidly connects transition after logical, because the voltage of current detecting terminal 30 is lower than threshold voltage vt h, so nmos pass transistor 46 is kept off-state, the electric current of LED16 flows through via resistor R 5.Therefore,, also can prevent to flow through among the LED16 overcurrent, can prevent in advance that LED16 from breaking down even the output voltage of switching regulaor 12 sharply raises when power connection.
Behind the power connection, if change stable state into from transition state, the voltage of current detecting terminal 30 is higher than threshold voltage vt h, and then nmos pass transistor 46 carries out ON Action, forms the bypass resistance of walking around resistor R 5, flows through predetermined electric current among the LED16.At this moment, because the electric current of LED16 flows through via nmos pass transistor 46, so generation power consumption can suppress stablize the time.
Flow through in LED16 in the process of predetermined electric current and produce when following the chattering phenomenon of load changing, the output of operational amplifier 50 changes low level into from high level, and nmos pass transistor 46 disconnects action immediately.Therefore, when the output voltage of switching regulaor 12 becomes high voltage subsequently,, also flow through electric current, therefore can suppress to flow through among the LED16 overcurrent via resistor R 5 even on switching regulaor 12, be connected with LED16.
According to present embodiment, when transition, be formed on the power-on circuit that comprises resistor R 5 in the supplying electric current path 52, by resistor R 5 current sinkings, can suppress to flow through among the LED16 overcurrent, on the other hand, when stablizing, in supplying electric current path 52, form the bypass resistance of walking around resistor R 5,, therefore can suppress power consumption by resistor R 5 current sinking not by nmos pass transistor 46.
Below, according to Fig. 6 the 2nd embodiment of the present invention is described.Replace protective circuit 14 in the present embodiment, be provided with protective circuit 54, other structure is identical with Fig. 1.In addition, in the 1st embodiment, make electric current begin to flow before or be transition state with the state of overcurrent, but in the present embodiment, only will produce over-current judging is transition state.
Protective circuit 54 has resistor R 5 is followed the electric current of energising as consumption resistive element; have nmos pass transistor 46, resistor R 6 as switch element; have the switch control unit of operational amplifier 50 as the switch motion of control switch unit, this protective circuit 54 is inserted between current detecting terminal 30 and the lead-out terminal 32.
Resistor R 5 is inserted in the supplying electric current path 52 that connects current detecting terminal 30 and lead-out terminal 32, at the two ends of resistor R 5, connects the drain electrode and the source electrode of nmos pass transistor 46 respectively.Negative input end of operational amplifier 50 is connected with current detecting terminal 30, the positive input terminal is connected with threshold voltage vt h, the voltage and the threshold voltage vt h that compare current detecting terminal 30, judge whether the electric current that flows through among the LED16 is the electric current of the transition state of expression overshoot scope, and output is corresponding to the voltage of judged result.
For example, when operational amplifier 50 is lower than threshold voltage vt h at the voltage of current detecting terminal 30, the electric current of judging LED16 is not the overcurrent of expression transition state, promptly is the electric current that is less than or equal to overcurrent, the voltage of output high level is as the judged result of negating, when the voltage of current detecting terminal 30 surpasses threshold voltage vt h, the electric current of judging LED16 is the overcurrent of expression transition state, and the voltage of output low level is as sure judged result.
If from the voltage of operational amplifier 50 output high level, then nmos pass transistor 46 carries out ON Action.If nmos pass transistor 46 carries out ON Action, then in the supplying electric current path 52 that connects current detecting terminal 30 and lead-out terminal 32, form the bypass resistance of walking around resistor R 5.
When nmos pass transistor 46 carries out ON Action, in supplying electric current path 52, form the bypass resistance of walking around resistor R 5, if flow through overcurrent but the electric current of following LED16 increases, then from the voltage of operational amplifier 50 output low levels, nmos pass transistor 46 disconnects action, forms the power-on circuit that comprises resistor R 5 in supplying electric current path 52.
That is,, then flow through electric current, owing to this electric current is consumed by resistor R 5, so can protect LED16 not influenced by overcurrent via the power-on circuit that comprises resistor R 5 if the electric current of LED16 becomes overcurrent.
According to present embodiment, when in LED16, flowing through overcurrent, comprise the power-on circuit of resistor R 5 owing in supplying electric current path 52, form, so can protect LED16 not influenced by overcurrent.